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Biomedical subjects

P Weidmann

Publications and source records attributed to P Weidmann.

At least 217 records · Page 12Linked to original sources
PubMed1982

Effect of standard oral glucose loading on aldosterone secretion in primary hyperaldosteronism.

The effects of mild acute decreases in plasma potassium induced by standard oral glucose loading (100 g) on plasma aldosterone and renin levels were assessed in 10 patients with primary hyperaldosteronism as compared with 10 normal subjects. Following overnight fast, mean plasma glucose was identical in both groups; plasma insulin, potassium and renin levels were lower and plasma aldosterone higher in patients than in controls. Glucose loading significantly increased plasma glucose and insulin concentrations and decreased plasma potassium and aldosterone levels in both groups. The increases in plasma insulin and the decreases in plasma potassium or aldosterone tended to be blunted in primary hyperaldosteronism. glucose-induced changes in plasma aldosterone correlated significantly (P less than 0.025) with those in plasma potassium in the patients and with variations in plasma renin activity in the normal subjects. These findings suggest that the metabolic changes induced by glucose ingestion are capable of modifying aldosterone secretion in primary hyperaldosteronism. However, the glucose-induced decreases in plasma aldosterone are blunted in this disorder; this could be related to the impaired insulin response to glucose loading.

Adult↗
PubMed1982

Effect of oral glucose loading on plasma insulin, potassium, renin and aldosterone in normal subjects and patients with primary hyperaldosteronism.

The effects of standard oral glucose loading (100 g) on plasma aldosterone and some regulatory factors were assessed in patients with primary hyperaldosteronism and normal subjects. Following overnight fast, mean plasma glucose was identical (10 patients and normal subjects approximately matched per age and sex); plasma insulin, potassium and renin levels were lower and plasma aldosterone higher in the patients. Glucose loading significantly increased plasma glucose and insulin concentrations and decreased plasma potassium and aldosterone levels in both groups; plasma renin activity was significantly increased only in normal subjects. The increases in plasma insulin and the decreases in plasma potassium or aldosterone tended to be blunted in primary hyperaldosteronism. Relationships among glucose-induced changes in plasma aldosterone and other factors were assessed by multiple regression analysis in these patients and normal subjects as well as an additional group of 21 normal subjects; in the latter, plasma cortisol was also measured and found to decrease significantly after glucose loading. Changes in plasma aldosterone correlated (P less than 0.025) more closely with those in plasma potassium in the patients and with variations in plasma renin activity in the normal subjects. These findings suggest that complex metabolic changes occur following glucose ingestion which are capable of modifying aldosterone secretion in normal subjects and primary hyperaldosteronism. The aldosterone-inhibitory effect of glucose tends to be blunted in the latter disorder. This could be related at least in part to an impaired insulin response in primary hyperaldosteronism.

Administration, Oral↗
PubMed1982

Menopause-dependent plasma lipoprotein alterations in diuretic-treated women.

The effects of chlorthalidone, 100 mg/d given for 6 weeks, on serum lipids and lipoproteins were assessed in 22 premenopausal and 18 postmenopausal women. In the latter, chlorthalidone significantly increased total serum cholesterol (13%, p less than 0.001), low-density-lipoprotein (LDL) cholesterol (21%, p less than 0.001) and apoprotein B (16%, p less than 0.05). In contrast, these values were not altered in the premenopausal group. Levels of LDL cholesterol, high-density-lipoprotein cholesterol, total and very-low-density triglycerides, apoproteins A1 and A2, and plasma volume, plasma glucose, insulin, epinephrine, estradiol, and free fatty acids were unchanged in both groups. Chlorthalidone-induced changes in levels of LDL cholesterol did not correlate significantly with variations in blood pressure, plasma potassium, uric acid, renin, aldosterone, or norepinephrine levels. These findings indicate that the thiazide-like diuretic chlorthalidone increases serum LDL cholesterol in postmenopausal but not in premenopausal women.

Adult↗
PubMed1982

Effects of acute mild hypercalcemia or of the calcium antagonist nifedipine on cardiovascular responsiveness to norepinephrine or angiotensin II in normal humans.

Pressor doses of infused norepinephrine (NE) (mean pressure, +20 mm Hg) or angiotensin II (AII) (diastolic pressure, +20 mm Hg) and corresponding blood levels of NE or AII were assessed in 12 young normal subjects under basal conditions (study A), during slow calcium infusion (0.034 mg/kg/min) started 60 min previously (study C), and following 2 weeks of treatment with the Ca antagonist nifedipine, 50 mg/day (study D). Control values of blood pressure, 24-h urinary sodium, plasma NE, epinephrine, AII, and renin activity did not differ among the three studies. Plasma Ca was higher during study C than during studies A and D [10.7 +/- 0.8 (+/- SD) versus 9.1 +/- 0.3 mg/dl; p less than 0.01]. Plasma NE or AII levels obtained during NE or AII infusion as well as the pressor doses of AII were not modified by concomitant Ca infusion or following nifedipine. However, compared with basal conditions, the NE pressor dose tended to be decreased slightly during Ca infusion (106 +/- 71 versus 77 +/- 38 ng/kg/min; difference not significant) and was increased markedly following nifedipine (178 +/- 87 ng/kg/min; p less than 0.05). A control infusion of Ca alone (study B) during 120 min did not modify blood pressure or plasma renin and NE levels. Our observations suggest that in normal humans, inhibition of cellular Ca transport may predominantly affect the noradrenergic control mechanism, whereas angiotensinogenic cardiovascular regulation may be less dependent.

Adult↗
PubMed1982

Catecholamines, sodium and renin in unilateral renal hypertension in man.

The relative roles of plasma or urinary norepinephrine (NE) and epinephrine (E), exchangeable sodium, blood volume, and plasma renin (PRA) or aldosterone in the pathogenesis of unilateral renal hypertension was evaluated. 99 normal subjects and 33 age-matched untreated hypertensive patients with unilateral renal parenchymal disease (RPD) (n = 18) or unilateral renal artery stenosis (RAS) (n = 15) were compared. Measurements were repeated following operative treatment in 23 patients. Plasma and urinary NE or E, exchangeable sodium and blood volume did not differ significantly between normal and untreated subjects with RPD or RAS. Both patient subgroups had increased blood pressure and supine PRA (p less than 0.001); these abnormalities were milder with RPD. Plasma aldosterone and upright PRA were significantly elevated (p less than 0.05) in RAS only. Operative treatment of RPD and RAS caused decreases in blood pressure (-18 and -28%) and PRA; they correlated in RPD (r = 0.56; p less than 0.05). In RPD and RAS, exchangeable sodium, blood volume, and NE or E values were not significantly changed following operation, except for mildly increased upright PNE in RAS. These observations suggest that the sympathetic system plays no major role in the maintenance of unilateral renal hypertension in man. However, the 'normal' body sodium-volume state in RPD or RAS may be inappropriate relative to coexisting hypertension. In addition to its established role in RAS, mild activation of the renin-angiotensin system may also be important for the pathogenesis of hypertension caused by unilateral RPD.

Adult↗
PubMed1982

Dialysis treatment of acute chromium intoxication and comparative efficacy of peritoneal versus hemodialysis in chromium removal.

External burns with chromic acid have been fatal even in cases with corrosions covering less than 10% of the body surface area. We observed a 19-year-old man with third-degree burns and chromium intoxication following accidental contact of both legs with chromium acid solution. The initial course was characterized by serum chromium levels known to be usually lethal (220 micrograms/100 ml), complete anuria, hepatic damage and progressive anemia. Aggressive peritoneal dialysis with a total duration of 252 h between the 4th and 22nd day after exposure caused a progressive decrease in serum chromium levels and resulted in a complete recovery after 35 days. The comparative efficacy of peritoneal versus hemodialysis in chromium removal was evaluated in 5 patients with acute renal failure who were treated with peritoneal dialysis and in 6 patients with end-stage renal failure who underwent hemodialysis. Following intravenous injection of 500 muCi51CrCl3 chromium clearance averaged 0.8 +/- 0.3 ml/min and 2.5 +/- 0.8 ml/min during peritoneal dialysis (n = 50) or hemodialysis (n = 24), respectively. It is concluded that hemodialysis is about 3 times as effective as peritoneal dialysis in chromium removal per unit of time. However, the possibility of applying uninterrupted peritoneal dialysis during the first few days suggests that this method is at least equivalent to hemodialysis for treatment in the initial stage of chromium intoxication.

Acute Disease↗
PubMed1982

Body sodium-blood volume state in nonazotemic diabetes mellitus.

Total exchangeable sodium and blood volume were measured in 126 diabetic patients without renal or heart failure, in 52 patients with essential hypertension and in 99 normal subjects. Both body constituents were judged using the body surface area as the frame of reference. Exchangeable sodium (ExNa) was significantly increased in diabetics as compared to normal subjects (110 vs. 100%), regardless of age, sex or body habitus. ExNa averaged 108% in the 63 diabetics with normal blood pressure, 111% in the 63 hypertensive diabetics and 99% in essential hypertension. Blood volume (BV) was normal or sometimes slightly low in the diabetics with normal or high blood pressure and in essential hypertension. In normal subjects, ExNa or BV were unrelated to age or systolic or diastolic blood pressure. In the diabetic population, ExNa correlated with the systolic blood pressure (r = 0.25; p less than 0.005) but not with the diastolic blood pressure or age; BV was unrelated to blood pressure. The correlation between ExNa and systolic blood pressure was closer in the diabetics with high blood pressure (r = 0.47; p less than 0.001); this relationship could not be explained by a concomitant influence of age or plasma creatinine (rp = 0.34; p less than 0.05). These findings indicate that an increased ExNa associated with a normal circulatory volume is a common abnormality in patients with nonazotemic diabetes mellitus. Excess body sodium may play an important pathogenetic role in the maintenance of diabetes-associated hypertension.

Adolescent↗
PubMed1981

Catecholamines, renin, aldosterone, and blood volume during chronic minoxidil therapy.

Several pressor factors were studied before and during chronic minoxidil therapy (median dose 27.5 mg/day) in 16 patients with hypertension that was refractory to conventional drugs. Following treatment with minoxidil and intensified diuretic therapy, blood pressure was decreased markedly; pulse rate, body weight, plasma volume, plasma aldosterone and epinephrine levels were not significantly altered, while plasma renin activity tended to be increased. Supine and upright plasma norepinephrine concentrations were increased by 140 (P less than 0.005) and 50% (P less than 0.05), respectively, but no significant change in urinary norepinephrine excretion was apparent. The latter parameter may not be a close index of sympathetic activity in patients with severe hypertension treated with minoxidil. While a search for underlying pheochromocytoma is always indicated in refractory hypertension, it appears mandatory to evaluate plasma catecholamines prior to or following discontinuation of treatment with minoxidil, to avoid a wrong diagnosis of pheochromocytoma.

Aldosterone↗
PubMed1981

Relationship between plasma catecholamines and urinary catecholamine excretion rates in normal subjects and certain diseased states.

Relationships between plasma norepinephrine (PNE) or epinephrine (PE) and urinary norepinephrine (UNE) or epinephrine (UE) excretion rates were studied in 37 normal subjects, 39 patients with benign essential hypertension, 23 with unilateral renal hypertension, and 20 with bilateral renal disease (serum creatinine 2.3 +/- 2.6 mg/100 ml). measurements were also performed after 6 weeks of diuretic treatment in 27 normal subjects and all patients with essential hypertension. In the untreated state, PNE and UNE values were generally normal in essential or unilateral renal hypertension; PNE tended to be decreased in diabetics and increased in bilateral renal disease. Diuretic treatment caused a tendency for slightly increased PNE and UNE. UNE correlated significantly with supine PNE or upright PNE or their mean value, and this relationship appeared to be comparable between untreated normal subjects and the various patients groups, except for a tendency for slightly higher PNE at given UNE values in bilateral renal disease. No significant correlations between UE and PE were apparent in the normal subjects or patient groups. These data demonstrate a dissociation of UE from PE levels. In contrast, UNE is an approximative index of PNE, and this relationship appeared to be generally unaltered in essential or unilateral renal hypertension. In patients with bilateral renal disease the slight shift of this relationship indicates that consideration of renal function is necessary for interpretation of NE levels.

Adult↗
PubMed1981

[New blood pressure-reducing medication].

The practicing physician is confronted daily with hypertension as a common disease and important cardiovascular risk factor. Many different antihypertensive agents are now available, but when and how should they be prescribed? The drugs which were available in Switzerland at the end of 1977 have already been reviewed in detail in this Journal (see Schweiz. med. Wschr. 108, 1 [1978]), but since then several new agents have been introduced. The author discusses the newer blood pressure-lowering drugs and their place in practical antihypertensive pharmacotherapy.

Adrenergic beta-Agonists↗
PubMed1981

Diuretic treatment and serum lipoproteins: effects of tienilic acid and indapamide.

Treatment with the commonly used diuretic, chlorthalidone, has previously been found to increase the serum low-density-lipoprotein cholesterol (LDL-C) fraction. Therefore, the effects of two new agents, tienilic acid (a combined diuretic-uricosuric) and indapamide on serum lipid and lipoprotein levels were assessed. Six weeks of treatment with tienilic acid, 250 mg/day, markedly decreased serum uric acid and significantly increased LDL-C and triglycerides in 16 men. In contrast, indapamide 2.5 mg/day, had no apparent influence on serum lipids or lipoproteins in 18 men.

Diuretics↗
PubMed1981

Chronic treatment with the new potent vasodilator Ro 12-4713 in moderate to severe hypertension: effects on blood pressure, endocrine function, sodium and plasma volume.

The antihypertensive efficacy and endocrine profile of the new antihypertensive agent, Ro 12-4713, were evaluated in 23 patients (17 men and 6 women) with moderate to severe arterial hypertension. Following addition of Ro 12-4713 to pre-existing therapy with diuretics and beta-blockers or sympatholytics, blood pressure in most of the patients was normalized within one month by a daily dose of 60 to 120 mg. Heart rate was only slightly increased. Orthostatic hypotension was not observed. Weight gain or oedema formation occurred in 14 patients within the first four weeks, but could be controlled satisfactorily by intensified diuretic therapy. Increased hair growth occurred in most of the patients. After a mean duration of treatment of 2.8 months, plasma volume and plasma and urine sodium were unaltered, and plasma potassium was slightly decreased. Plasma renin activity was doubled, whereas plasma aldosterone concentrations were unaltered. Plasma norepinephrine levels were high before and increased only slightly during chronic Ro 12-4713 treatment, whereas urinary norepinephrine excretion was unchanged. Plasma and urinary epinephrine were unaltered by Ro 12-4713. Ro 12-4713 appears to be a potent vasodilator for the combination treatment of hypertension in men.

Adult↗
PubMed1981

Exaggerated pressor responsiveness to norepinephrine in nonazotemic diabetes mellitus.

Pressor responses to norepinephrine (NE) or angiotensin II (AII) were studied in 27 diabetic patients without heart or renal failure and in 27 normal subjects. Mean plasma or 24-hour urinary sodium, blood volume and preinfusion plasma NE levels were similar in diabetic and normal subjects; exchangeable sodium was higher (p less than 0.02) and preinfusion plasma renin activity (PRA) was slightly lower in diabetic patients. The NE pressor and threshold doses were lower in diabetic patients than in normal subjects (76 versus 141 and 16 versus 41 ng/kg/min, respectively; p less than 0.05). The AII pressor dose also tended to be lower in diabetic patients (7.2 versus 11.9 ng/kg/min; p less than 0.05), but the AII threshold dose did not differ between the two groups (1.1 versus 1.6 ng/kg/min). These findings were similar in the diabetic subgroup without or with retinopathy (N = 13 and 14, respectively) and in those with normal or high blood pressure (N = 17 and 10, respectively). These observations suggest that in nonazotemic diabetes mellitus increases in AII pressor responsiveness are associated with a concomitant reduction in PRA. However, cardiovascular pressor responsiveness to NE tends to be exaggerated despite normal plasma NE levels and this alteration may occur already in the normotensive stage of diabetes mellitus. Cardiovascular hyperresponsiveness in diabetic subjects may be related to excess body sodium or structural alterations in the vasculature, or both.

Adult↗
PubMed1981

Acute hypercalcemic hypertension in man: role of hemodynamics, catecholamines, and renin.

The effect of acute hypercalcemia on blood pressure, blood volume, hemodynamic parameters, plasma norepinephrine, epinephrine, dopamine, renin, and aldosterone concentrations was investigated. After 1 hour of equilibration, 10 patients received an infusion of calcium gluconate in 5% dextrose (calcium 15 mg/kg of body wt in 3 hours). The calcium infusion increased the mean serum calcium from 8.7 to 13.0 mg/dl, the systolic blood pressure from 144 +/- 10 to 184 +/- (SEM) 12 mm Hg (P less than 0.001), the diastolic pressure from 78 +/- 4 to 93 +/- 5 mm Hg (P less than 0.01). The plasma volume was decreased by 9% (P less than 0.001), whereas the hematocrit was increased (P less than 0.05). Heart rate and cardiac output remained unchanged. Total peripheral resistance was increased from 1643 +/- 223 to 2256 +/- 387 dyne.sec/cm5 (P less than 0.05). The plasma epinephrine concentration rose from 4.5 +/- 0.7 to 6.9 +/- 1.2 ng/dl (P less than 0.01). The plasma norepinephrine concentration was unchanged after 2 hours and increased only slightly after 3 hours of calcium infusion. Plasma renin, aldosterone, and dopamine concentrations were not significantly changed. These findings demonstrate that acute hypercalcemic hypertension is mediated by an increase in peripheral vascular resistance. Hypercalcemic hypertension may be induced by a direct effect of calcium on blood vessels; calcium-mediated increase in adrenal epinephrine release may play a mild contributory role, and plasma volume contraction, an inhibitory role.

Adult↗